Clarify resume hints for renamed threads (#23234)

Addresses #23181

## Why
Renamed threads can share names, so hints that suggest resuming directly
by name are ambiguous. Issue #23181 asks for the picker hint to include
the thread name and thread ID in parens so users can disambiguate
safely.

## What
- Adds a shared resume hint formatter for named threads: run `codex
resume`, then select `<name> (<thread-id>)`.
- Uses that hint for /rename confirmations, TUI session summaries, and
CLI/TUI exit messages.
- Keeps direct `codex resume <thread-id>` guidance for unnamed threads.

## Verification
Manually verified that message after `/rename` and after `/exit` include
session ID in parens.

---------

Co-authored-by: Felipe Coury <felipe.coury@openai.com>

codex-rs/utils/cli/src/lib.rs

@@ -10,5 +10,6 @@ pub use codex_protocol::config_types::ProfileV2Name;
 pub use config_override::CliConfigOverrides;
 pub use format_env_display::format_env_display;
 pub use resume_command::resume_command;
+pub use resume_command::resume_hint;
 pub use sandbox_mode_cli_arg::SandboxModeCliArg;
 pub use shared_options::SharedCliOptions;